1. Field of the Invention
The present invention relates to a digital signal coding apparatus for digitizing and compressing image data and for recording the compressed digital data to a magnetic tape or the like.
2. Related Background Art
Hitherto, in a digital VTR of the compression type, image data is high efficient coded and recorded. As a high efficient coding, image data which was orthogonal converted is quantized and the quantized data is coded by a variable length code. In this instance, in a code amount estimation unit, a quantization unit is adaptably changed and a coefficient of the quantization unit is decided so as to set a code amount to a predetermined rate. A correction code and information necessary for a block such as Sync, ID, and the like are added to the data which was set to the fixed rate. The resultant data is recorded to a tape medium as a sync block format.
On the other hand, generally, audio data is not compressed but an error correction code is added to the audio data. The resultant data is recorded into an audio area provided separately from the image data. In such a manner, the audio data has been determined by the format so as to be recorded at a determined position.
In the above conventional example, however, the position at which the audio data, image data, or the like is written has been decided by the format and an area to write data as necessary doesn't exist. Therefore, there is a drawback such that no data can be additionally written.